The present invention generally relates to the storage and retrieval of electronic data used in computer systems. More particularly, the present invention relates to systems and methods for managing the storage of electronic data on recordable medium that extends the amount of time the electronic data may be retrieved from the recordable medium before the medium is reused in another storage application.
The storage of electronic data has evolved over time. During the early development of the computer, storage of electronic data was limited to individual computers. Electronic data was stored in the Random Access Memory (RAM) or some other storage medium such as a magnetic tape or hard drive that was a part of the computer itself.
Later, with the advent of network computing, the storage of electronic data gradually migrated from the individual computer to stand-alone storage devices accessible via a network. These individual network storage devices soon evolved into networked tape drives, optical libraries, Redundant Arrays of Inexpensive Disks (RAID), CD-ROM jukeboxes, and other devices. Common architectures included drive pools, which generally are logical collections of drives with associated media groups including magnetic tapes or other storage media used by a given drive pool.
Storage systems, such as some of the systems described above, typically employ certain high capacity data storage mediums, which may include magnetic tapes, optical disks and the like to store electronic information. At some point in time, however, it is often no longer necessary or desirable to retain the electronic information stored on these media. When this point is reached, the media on which such electronic information is stored may be reused or recycled by the system for use in other storage jobs rather than simply discarding the media or maintaining the information in perpetuity.
For example, in a tape-based system, a storage tape with unwanted or outdated information may be designated within the storage management system for reuse in a subsequent storage operation in a spare media pool. Such a spare media pool may contain media that is available for storage use in subsequent storage operations and may include new media or media designated for reuse within the storage system. When storage media are assigned to the spare media pool, any information in the storage management system regarding the old data on the tape may be discarded, erased or designated for overwrite and replaced with a simple designation indicating that the tape is available for use in another storage operation. For example, an index entry used by the storage management system that includes information about the old data may be overwritten of renamed to after the data retention period has expired.
In many storage systems, however, the reused storage media continues to contain the data from the previous storage operation, which typically remains on the media until it is overwritten by a new storage process. Thus, in many storage systems, the media designated for reuse continues to contain old information for a significant period of time past any established retention date. Nevertheless, because records are not typically retained or retrievable by storage management systems regarding the media designated for reuse (and any old information contained thereon), it is difficult to recover or restore any of this old information, absent the use of cumbersome, uncommon restore procedures, despite the fact that the such information still exists on media designated for reuse within the system.
Accordingly, what is needed are systems and methods that overcome this and other deficiencies.